Method of manufacturing display apparatus and display apparatus manufactured using the same

ABSTRACT

A method of manufacturing a display apparatus includes preparing a substrate including a display area and a pad area outside of the display area, forming a sacrificial layer in the pad area, forming an encapsulation layer over the display area and the pad area, forming cracks in at least a portion of the encapsulation layer by increasing a volume of the sacrificial layer or by gasifying or evaporating at least a portion of the sacrificial layer, and removing at least a portion of the encapsulation layer in the pad area. A display apparatus is manufactured according to the manufacturing method.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.15/203,022, filed Jul. 6, 2016, which claims priority to and the benefitof Korean Patent Application No. 10-2015-0184079, filed Dec. 22, 2015,the entire content of both of which is incorporated herein by reference.

BACKGROUND 1. Field

One or more embodiments relate to a method of manufacturing a displayapparatus and a display apparatus manufactured using the same. Forexample, one or more embodiments relate to a method of manufacturing adisplay apparatus according to a simplified manufacturing process and adisplay apparatus manufactured using the same.

2. Description of the Related Art

Generally, a display apparatus includes a plurality of display elements,which are disposed on a substrate, and a pad, which is electricallycoupled to (e.g., electrically connected to) the display elements. Whenvarious suitable electrical signals are applied to the display elements,the various suitable electrical signals are applied to the displayelements through the pad.

Meanwhile, in order to protect the display elements, the displayapparatus includes an encapsulation layer to at least partially coverthe display elements. When the encapsulation layer is formed, the pad,to which the electrical signals are applied, needs to be exposed by theencapsulation layer. Accordingly, when the encapsulation layer isformed, a mask is used to form the encapsulation layer only (orsubstantially only) in a set (e.g., predetermined) area of thesubstrate.

However, since, in a method of manufacturing a display apparatus, themask is used repeatedly to form the encapsulation layer and thus resultsin being damaged, the mask needs to be replaced with a new oneperiodically when the display apparatus is manufactured. Accordingly,the method of manufacturing a display apparatus has problems thatmanufacturing costs increase, and a process of precisely aligning themask and the substrate relative to each other during the manufacture ofthe display apparatus.

SUMMARY

One or more embodiments include a method of manufacturing a displayapparatus and a display apparatus manufactured using the same.

Additional aspects of embodiments will be set forth in part in thedescription which follows and, in part, will be apparent from thedescription, or may be learned by practice of the presented embodiments.

According to one or more embodiments, a method of manufacturing adisplay apparatus includes preparing a substrate including a displayarea and a pad area outside of the display area, forming a sacrificiallayer in the pad area, forming an encapsulation layer over the displayarea and the pad area, forming cracks in at least a portion of theencapsulation layer by increasing a volume of the sacrificial layer orby gasifying or evaporating at least a portion of the sacrificial layer,and removing at least a portion of the encapsulation layer in the padarea.

The forming of the sacrificial layer may include concurrently (e.g.,simultaneously) forming the organic layer in the display area and thesacrificial layer.

The forming of the sacrificial layer may include concurrently (e.g.,simultaneously) forming an intermediate layer interposed between a pixelelectrode and an opposite electrode in the display area, and thesacrificial layer.

The method may further include forming a display element in the displayarea. The forming of the sacrificial layer may include concurrently(e.g., simultaneously) forming a capping layer including an organiccompound and at least partially covering the display element in thedisplay area, and the sacrificial layer.

The forming of the cracks may include irradiating a laser beam to (e.g.,into) the portion of the encapsulation layer which is disposed above thesacrificial layer.

The forming of the cracks may include using the laser beam having anabsorbance in an organic compound greater than an inorganic compound.

The forming of the encapsulation layer may include forming an inorganiclayer.

The method may further include increasing an area of the encapsulationlayer, in which the cracks are formed, by applying a force to theencapsulation layer which is disposed above the sacrificial layer.

The increasing of the area may include using a roller.

The forming of the encapsulation layer may include forming a firstinorganic encapsulation layer over the display area and the pad area,forming an organic encapsulation layer over the first inorganicencapsulation layer, the organic encapsulation layer including a firstportion corresponding to the display area and a second portion separatefrom the first portion and corresponding to the pad area, and forming asecond inorganic encapsulation layer in the display area and the padarea to at least partially cover the first portion and the secondportion of the organic encapsulation layer.

An adhesive force between the first inorganic encapsulation layer andthe organic encapsulation layer may be greater than an adhesive forcebetween the first inorganic encapsulation layer and the sacrificiallayer.

The removing of the portion of the encapsulation layer may includeremoving at least a portion of the first inorganic encapsulation layerin the pad area, the entire second portion of the organic encapsulationlayer, and at least a portion of the second inorganic encapsulationlayer in the pad area.

The method may further include forming an additional organic layer overthe at least a portion of the encapsulation layer which is disposed overthe sacrificial layer, and the removing of the portion of theencapsulation layer may include removing the portion of theencapsulation layer, which is over the sacrificial layer, and the entireadditional organic layer.

An adhesive force between the encapsulation layer and the additionalorganic layer may be greater than an adhesive force between theencapsulation layer and the sacrificial layer.

According to one or more embodiments, a display apparatus may include asubstrate including a display area and a pad area outside of the displayarea, display elements disposed in the display area, and anencapsulation layer at least partially covering the display area to atleast partially cover the display elements, wherein a roughness of afirst end surface of the encapsulation layer in a pad area direction isgreater than a roughness of a second end surface of the encapsulationlayer in a direction opposite to the pad area direction.

The encapsulation layer may include a first inorganic encapsulationlayer at least partially covering the display area and the pad area, anorganic encapsulation layer disposed over the first inorganicencapsulation layer and having an area less than an area of the firstinorganic encapsulation layer, and a second inorganic encapsulationlayer disposed over the organic encapsulation layer and contacting thefirst inorganic encapsulation layer outside of the organic encapsulationlayer. The encapsulation layer may include a first end surface having alower end surface most adjacent to the substrate, an upper end surfacefarthest from the substrate, and an intermediate end surface between thelower end surface and the upper end surface. A roughness of the lowerend surface and a roughness of the upper end surface may be greater thana roughness of the intermediate end surface.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIGS. 1-9 are respective cross-sectional views and plan views,schematically illustrating processes of a method of manufacturing adisplay apparatus according to embodiments of the presently disclosedsubject matter;

FIG. 10 is a cross-sectional view schematically illustrating a processof a method of manufacturing a display apparatus according to anembodiment;

FIGS. 11 and 12 are cross-sectional views schematically illustrating aprocess of a method of manufacturing a display apparatus according to anembodiment; and

FIG. 13 is a cross-sectional view schematically illustrating a processof a method of manufacturing a display apparatus according to anembodiment.

DETAILED DESCRIPTION

The present embodiments may have different forms and should not beconstrued as being limited to the descriptions set forth herein.Accordingly, embodiments are merely described below, by referring to thefigures, to explain aspects of the present description.

Reference will now be made in more detail to embodiments, examples ofwhich are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. Duplicatedescriptions thereof will not be provided.

Sizes of elements in the drawings may be exaggerated for convenience ofexplanation. In other words, since sizes and thicknesses of componentsin the drawings may be arbitrarily illustrated for convenience ofexplanation, the following embodiments are not limited thereto.

In the following examples, the x-axis, the y-axis and the z-axis are notlimited to three axes of the rectangular coordinate system, and may beinterpreted in a broader sense. For example, the x-axis, the y-axis, andthe z-axis may be perpendicular (e.g., substantially perpendicular) toone another, or may represent different directions that are notperpendicular to one another.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

FIGS. 1 through 9 are respective cross-sectional views and plan views,schematically illustrating processes of a method of manufacturing adisplay apparatus according to embodiments of the presently disclosedsubject matter.

In the method according to embodiments of the present disclosure, asubstrate 100 is prepared. The substrate 100 of FIG. 1 may be a mothersubstrate which is used to manufacture a plurality of displayapparatuses. As described later herein, the substrate 100 of FIG. 1 iscut and separated into a plurality of substrates 101, 102, and 103 ofthe respective display apparatuses. The substrate 100 includes a displayarea DA and a pad area PD which is disposed outside of the display areaDA, as illustrated in FIG. 2. In more detail, the substrate 100 includesa plurality of areas which are subsequently separated from each otherand each of which includes the display area DA and the pad area PDdisposed outside of the display area DA. The substrate 100 may include aplastic material such as, for example, polyimide or another material.

After the substrate 100 is prepared, one or more display elements 300are disposed in the display area DA, and a pad 410 is disposed in thepad area PA, as illustrated in FIG. 3. FIG. 3 is a cross-sectional viewillustrating a portion of the display area DA and a portion of the padarea PA and may be a cross-sectional view taken along a line III-III ofFIG. 2. In this case, it is understood that elements, which are formedon the display area DA and the pad area PA, may be omitted from FIG. 2for clarity.

In addition to the display elements 300 in the display area DA of thesubstrate 100, a thin film transistor 210, which is electrically coupledto (e.g., electrically connected to) the display element 300, may alsobe disposed in the display area DA, as illustrated in FIG. 3. In FIG. 3,the display element 300 may include an organic light-emitting element(hereinafter, referred to as the organic light-emitting element 300).The organic light-emitting element 300 is electrically coupled to (e.g.,electrically connected to) the thin film transistor 210 when a pixelelectrode 310 is electrically coupled to (e.g., electrically connectedto) the thin film transistor 210. If necessary or desired, a thin filmtransistor may be disposed in a peripheral area, e.g., the pad area PA,of the substrate 100. The thin film transistor disposed in the pad areaPA of the substrate 100 may be a portion of a circuit to controlelectrical signals which are applied to the display area DA.

The thin film transistor 210 may include a semiconductor layer 211 whichincludes, for example, amorphous silicon, polysilicon, or an organicsemiconductor material, a gate electrode 213, a source electrode 215,and a drain electrode 217. In order to insulate the semiconductor layer211 from the gate electrode 213, a gate insulating layer 120 may bebetween the semiconductor layer 211 and the gate electrode 213 and mayinclude silicon oxide and/or silicon nitride. An interlayer insulatinglayer 130 may be disposed over the gate electrode 213 and may includesilicon oxide and/or silicon nitride. The source electrode 215 and thedrain electrode 217 may be disposed over the interlayer insulating layer130.

In some embodiments, in order to protect the thin film transistor 210, aprotection layer may at least partially cover (e.g., completely cover)the thin film transistor 210. The protection layer may include aninorganic compound such as silicon oxide, silicon nitride, and/orsilicon oxynitride. The protection layer may be a single layer or amultilayer. A planarization layer 140 may be disposed over theprotection layer. For example, when the organic light-emitting element300 is disposed over the thin film transistor 210, as illustrated inFIG. 3, the planarization layer 140 may planarize an upper surface ofthe protection layer, which at least partially covers (e.g., completelycovers) the thin film transistor 210. The planarization layer 140 mayinclude an acryl-based organic compound or benzocyclobutene (BCB).Although FIG. 3 illustrates that the planarization layer 140 is a singlelayer, the planarization layer 140 may be a multilayer. The displayapparatus according to embodiments of the present disclosure may includeboth the protection layer and the planarization layer 140 or may includeone selected from the protection layer and the planarization layer 140.

In the display area DA of the substrate 100, the organic light-emittingelement 300 may be disposed over the planarization layer 140, and mayinclude the pixel electrode 310, an opposite electrode 330, and anintermediate layer 320 between the pixel electrode 310 and the oppositeelectrode 330. The pixel electrode 310 may be electrically coupled to(e.g., electrically connected to) the thin film transistor 210 bycontacting one selected from the source electrode 215 and the drainelectrode 217 of the thin film transistor 210 through an opening whichis formed in the planarization layer 140, as illustrated in FIG. 3.

A pixel defining film 150 may be disposed over the planarization layer140. The pixel defining film 150 defines a pixel by forming an openingtherein, which exposes at least a center portion of the pixel electrode310 to the outside (e.g., allows light to be transmitted from at least acenter portion of the pixel electrode 310 to the outside). Asillustrated in FIG. 3, the pixel defining film 150 increases a distancebetween a boundary of the pixel electrode 310 and the opposite electrode330, which is disposed above the pixel electrode 310, to prevent theoccurrence of an arc from the boundary of the pixel electrode 310 (or toreduce a likelihood or amount of such arcing). The pixel defining film150 may include an organic compound such as, for example, polyimide.

The intermediate layer 320 of the organic light-emitting element 300 mayinclude a small molecule material and/or a polymer material. When theintermediate layer 320 includes a low molecular weight material, theintermediate layer 320 may include a single layer or a multilayerstacked in a composite structure including a hole injection layer (HIL),a hole transport layer (HTL), an emissive layer, an electron transportlayer (ETL), and/or an electron injection layer (EIL), and may includeat least one selected from organic compounds and/or organometalliccompounds, such as, for example, copper phthalocyanine (CuPc),N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), andtris(8-hydrooxyquinoline)aluminum (Alq3). The above layers may be formedaccording to a vacuum deposition process.

When the intermediate layer 320 includes a polymer material, theintermediate layer 320 may include the HTL and an emissive layer. Here,the HTL may include, for example, poly(3,4-ethylenedioxythiophene)(PEDOT), and the emissive layer may include a polymer material such as,for example, a poly(p-phenylenevinylene) (PPV)-based material and apolyfluorene-based polymer material. The intermediate layer 320 may beformed according to a screen print method, an inkjet printing method, ora laser induced thermal imaging (LITI) method.

The intermediate layer 320 is not limited to the above-describedstructure, but may have at least one of various suitable structures. Theintermediate layer 320 may be an integrated layer through the pluralityof pixel electrodes 310 or a patterned layer to correspond to each ofthe plurality of pixel electrodes 310.

The opposite electrode 330 is disposed over the display area DA, and theopposite electrode 330 may at least partially cover (e.g., completelycover) the display area DA, as illustrated in FIG. 3. For example, theopposite electrode 330 includes a plurality of organic light-emittingelements 300 which are integrated to correspond to the plurality ofpixel electrodes 310.

A plurality of pads 410 may be disposed on pad areas PA of the substrate100. As illustrated in FIG. 3, the plurality of pads 410 may be disposedover the interlayer insulating layer 130, e.g., over the same layer asthe source electrode 215 and the drain electrode 217. In this case, theplurality of pads 410 may include the same material (e.g., substantiallythe same material) as the source electrode 215 and the drain electrode217, and may be concurrently (e.g., simultaneously) formed together withthe source electrode 215 and the drain electrode 217 according to amanufacturing process. However, the present disclosure is not limitedthereto. Various suitable processes may be used to form the pads 410.For example, the pads 410 and the gate electrode 213 may be concurrently(e.g., simultaneously) formed and may include the same material (e.g.,substantially the same material).

As such, after the display elements 300 and the pads 410 are formed inthe display area DA and the pad area PA of the substrate 100,respectively, a sacrificial layer 420 is formed over the pad area PA, asillustrated in FIG. 3. The sacrificial layer 420 may at least partiallycover (e.g., completely cover) the entire (e.g., substantially theentire) pad area PA or may at least partially cover (e.g., completelycover) a portion of the pad area PA. For example, FIG. 3 illustratesthat the sacrificial layer 420 at least partially covers (e.g.,completely covers) the pad 410 of the pad area PA.

Although the sacrificial layer 420 may be formed independently fromother elements of the display apparatus, the sacrificial layer 420 maybe concurrently (e.g., simultaneously) formed together with at least oneof the other elements of the display apparatus. For example, when theintermediate layer 320 is formed in the display area DA, the sacrificiallayer 420 may be formed with the same material (e.g., substantially thesame material) as the intermediate layer 320. In more detail, when theHIL or the ETL is formed in the display area DA, the sacrificial layer420 may be concurrently (e.g., simultaneously) formed in the pad area PAwith the same material (e.g., substantially the same material) as theHIL or the ETL when the HIL or the ETL is formed in the display area DA.A buffer layer 110 may be disposed between the between the substrate 100and the gate insulating layer 120 and/or between the substrate 100 andthe semiconductor layer 211.

Thereafter, as illustrated in FIG. 4, an encapsulation layer 500 isformed through the display area DA and the pad area PA. Theencapsulation layer 500 may be a single layer or a multilayer. When theencapsulation layer 500 is a single layer, the encapsulation layer 500may include an inorganic layer. When the encapsulation layer 500 is amultilayer, the encapsulation layer 500 may include an inorganic layerand an organic layer. The inorganic layer may be formed according to adeposition process, and the inorganic layer may include, for example,silicon nitride, silicon oxide and/or silicon oxynitride or may includemetal oxide, metal nitride, metal oxynitride, and/or metal carbide. Theorganic layer may include, for example, polyacrylate, polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), polycarbonate,polyimide, polyethylene sulfonate, polyoxymethylene, polyarylate, and/orepoxy.

After the encapsulation layer 500 is formed, the substrate 100 is cut toform a plurality of display apparatuses. The substrate 100 may be cutalong cutting lines CL1, CL2, CL3, and CL4, as illustrated in FIG. 2.For example, the substrate 100 may be cut by irradiating a laser beamalong the cutting lines CL1, CL2, CL3, and CL4. Here, because thecutting lines CL1 and CL2 and the cutting line CL3 may pass through atleast a portion of the pad area PA, as illustrated in FIG. 2, the laserbeam may be controlled to pass through at least a portion of thesacrificial layer 420 when the laser beam is irradiated on or to thesacrificial layer. The cutting line CL3 passes through the sacrificiallayer 420, as illustrated in FIG. 5.

By irradiating the laser beam into the sacrificial layer 420 when thelaser beam is irradiated along the cutting lines CL1, CL2, and CL3, atleast a dimension of the portion of the sacrificial layer 420 increasesor the portion of the sacrificial layer 420 is gasified or evaporated.At this time, when at least a dimension of the portion of thesacrificial layer 420 increases or at least the portion of thesacrificial layer 420 is gasified or evaporated, cracks CR may be formedin the portion of the encapsulation layer 420 which is disposed over thesacrificial layer 420. For example, by irradiating the laser beam intothe sacrificial layer 420, the portion of the sacrificial layer 420,into which the laser beam is irradiated, increases or is gasified orevaporated, and thus, cracks CR may be formed in the portion of theencapsulation layer 500 which corresponds to the portion of thesacrificial layer 420. For this reason, the encapsulation layer 500 mayinclude an inorganic layer. The inorganic layer may easily generate thecracks CR when a layer below the inorganic layer is changed in volume ordeformed in shape.

The cross-sectional view of FIG. 5 illustrates a state in which a volumeof the portion of the sacrificial layer 420 is increased, and the planview of FIG. 6 after cutting the substrate 100 illustrates the cracks CRin the pad area PA of the encapsulation layer 500 which at leastpartially covers (e.g., completely covers) the display area DA and thepad area PA. The cutting lines CL1, CL2, and CL3 pass through the padareas Pas, as illustrated in FIG. 2, cracks CR are generated in areas ofthe encapsulation layer 420, which are disposed adjacent to the cuttinglines CL1, CL2, and CL3, and below which the sacrificial layer 420 isdisposed. Although FIG. 5 illustrates that the substrate 100 does notshow the cut along the cutting line CL3 for convenience, the substrate100 is cut along the cutting line CL3.

Although the laser beam is irradiated onto the portion of theencapsulation layer 500 which is disposed on the sacrificial layer 420,if the laser beam is an infrared laser beam, most of the infrared laserbeam arrives at the sacrificial layer 420 after passing through theinorganic layer of the encapsulation layer 500, As a result, the portionof the sacrificial layer 420, into which the laser beam is irradiated,may be changed in volume or may be gasified or evaporated. If the laserbeam is absorbed by the inorganic layer of the encapsulation layer 500,the encapsulation layer 500 itself may be cut without the cracks CRformed therein. In this case, even if the cracks CR are generated in theencapsulation layer 500, an area of the encapsulation layer 500, inwhich the cracks CR are generated, is very small, and the cracks CRwhich are formed in the pad area PA of the encapsulation layer 500 maynot easily grow as described later herein. Accordingly, the laser beam,which is used to cut the substrate 100, may be a laser beam having ahigher absorbance by an organic compound than an inorganic compound(e.g., the organic compound described herein may absorb more of thelaser beam than the inorganic compound described herein).

Meanwhile, when the substrate 100 is cut by using the laser beam, evenif the laser beam is absorbed by the inorganic layer of theencapsulation layer 500 and thus the encapsulation layer 500 is cut, thelaser beam is also concurrently (e.g., simultaneously) absorbed by thesacrificial layer 420, and thus the portion of the sacrificial layer 420may be changed in volume or may be gasified or evaporated so that thecracks CR are generated in the encapsulation layer 500.

The more that cracks CR are generated in the encapsulation layer 500,the more of an area of the encapsulation layer 500, in which the cracksCR are generated, is enlarged, as described later herein. Accordingly,when the sacrificial layer 420 is formed, a width of the sacrificiallayer 420 in a lengthwise direction (Y direction) is greater than awidth of the display area DA in the lengthwise direction (Y direction),and thus, it is desirable that the cutting line CL3, which extends inthe lengthwise direction (Y direction) of the sacrificial layer 420, aswell as the cutting lines CL1 and CL2, which extend in a direction (Xdirection) which intersects the lengthwise direction (Y direction), maypass therethrough, as illustrated in FIG. 2. Accordingly, cracks CR maybe generated along three boundaries of the pad area PA with respect to aplan view, as illustrated in FIG. 6.

As such, after the cracks CR are generated in the portion of theencapsulation layer 500 which is disposed above the sacrificial layer420, at least the portion of encapsulation layer 500 in the pad area PAmay be removed. Before this, as illustrated in FIG. 7, the area of theencapsulation layer 500, in which the cracks CR are generated, may beincreased by applying a force to the portion of the encapsulation layer500 which is disposed above the sacrificial layer 420 (e.g., an amountof the cracks CR may be increased by applying a force to the portion ofthe encapsulation layer 500 which is disposed above the sacrificiallayer 420). For example, a roller RL may move on the pad area PA from aportion of the display area DA to a boundary of the substrate 100 in anarrow direction AR1 (+X direction). Here, the roller RL may move while aforce is applied in a direction (−Z direction) of the substrate 100(e.g., the force may be applied toward the substrate 100), and thus,cracks CR may grow in the pad area PA to increase the area of theencapsulation layer 500 in which the cracks CR are formed.

Here, the roller RL may not only move from a boundary of the substrate100, in which the cracks CR are formed, to the display area DA in adirection (−X direction) but also may move from the display area DA(e.g., from a boundary of the display area DA) to the boundary of thesubstrate 100 in the direction AR1 (+X direction). When the roller RLmay not only move from the boundary of the substrate 100 in which thecracks CR are formed to the display area DA (e.g., to the boundary ofthe display area DA) in the direction AR1 (−X direction), it is possiblethat the performance of the encapsulation layer 500 may be degraded anddefects may occur when the already-grown cracks CR are overgrown towardan inside of the display area DA.

Thereafter, when the roller RL moves from the boundary of the pad areaPA of the substrate 100 in an arrow direction AR2 parallel to theboundary of the pad area PA of the substrate 100, the portion of theencapsulation layer 500, which is weakened by the generated cracks CR,may be separated from the substrate 100. For example, when the roller RLmoves from the display area DA (e.g., from the boundary of the displayarea DA) to the boundary of the substrate 100 in the direction AR1 (+Xdirection), the roller RL may roll. However, when the roller RL movesfrom the boundary of the pad area PA of the substrate 100 in the arrowdirection AR2, the roller RL may not roll, but a force applied to theroller RL may cause the portion of the encapsulation layer 500, in whichthe cracks CR are formed, to slide, and thus the portion of theencapsulation layer 500 may be separated from the substrate 100 and mayprotrude as a convex shape in an upper direction (+Z direction). Throughthis process, the portion of the encapsulation layer 500 may be removedin the pad area PA of the substrate 100, as illustrated in thecross-sectional view of FIG. 8 and the plan view of FIG. 9. Accordingly,the encapsulation layer 500 no longer covers (e.g., no longer completelycovers) the pad 410, and thus a printed circuit board or an electricalchip may be electrically coupled to (e.g., electrically connected to)the pad 410.

A process of removing the portion of the encapsulation layer 500 in thepad area PA of the substrate 100 may not be limited to theabove-described process using the roller RL. For example, at least oneof various suitable processes may be used such as, for example, anadhesive tape may be used to remove the portion of the encapsulationlayer 500 in which the cracks CR are formed.

In a method of manufacturing the display apparatus according to anembodiment of the present disclosure, when the encapsulation layer 500is formed, it is not necessary to use any additional separate mask sothat the encapsulation layer 500 is not formed on the pad area PA.Accordingly, since a mask is not used to form the encapsulation layer500 in the manufacturing method, it is not necessary to align the maskand the substrate 100 relative to each other, manufacturing costs maydecrease, and the manufacturing method is simplified.

Meanwhile, it may be necessary or desired to separate the portion of theencapsulation layer 500, in which the cracks CR are formed, from thesubstrate 100, for example, from lower elements which are disposed belowthe encapsulation layer 500. For this, the sacrificial layer 420 mayhave a low adhesiveness with or to the lower elements. As describedabove, in the case of the organic compound of the hole injection layer(HIL) or the electron transport layer (ETL), since the adhesiveness ofthe organic compound to the pad 410 including a metal and the interlayerinsulating layer 130 including the inorganic compound is low, thesacrificial layer 420 may be concurrently (e.g., simultaneously) formedtogether with the above-described layer (e.g., HIL or EIL) by using thesame material (e.g., substantially the same material) as theabove-described layer (e.g., the HIL or ETL). Therefore, embodiments ofthe manufacturing method may be simplified, and the encapsulation layerin the pad area PA may be easily removed.

In the organic light-emitting display apparatus manufactured accordingto the above-described method, a roughness of a first end surface 501ES(FIGS. 8 and 9) of the encapsulation layer 500 facing the pads 410 isgreater than a roughness of a second end surface 502ES (FIG. 9) of theencapsulation layer 500 facing away the pads 410 and roughnesses ofthird and fourth end surfaces 503ES and 504ES of the encapsulation layer500 in other directions. The roughness of the first end surface 501ES(FIGS. 8 and 9) of the encapsulation layer 500 becomes greater since ofthe encapsulation layer 500 in the pad area PA is removed after thecracks CR are formed in the encapsulation layer 500 and then the formedcracks CR are grown. The roughnesses of the second, third, and fourthend surfaces 502ES, 503ES, and 504ES become relatively lower since theencapsulation layer 500 is cut by irradiating the laser beam. Forexample, the roughness of the first end surface 501ES of theencapsulation layer 500 may be a root mean square (RMS) value of about18.85 μm (e.g., the first end surface 501ES of the encapsulation layer500 may have a root mean square (RMS) roughness value of about 18.85μm).

In the roughnesses of the second, third, and fourth end surfaces 502ES,503ES, and 504ES of the encapsulation layer 500, the second, third, andfourth end surfaces 502ES, 503ES, and 504ES of the encapsulation layer500 are cut relatively cleanly since the substrate 100 is cut by heat,which is generated by the laser beam passing the encapsulation layer 500during the cutting of the substrate 100.

FIG. 10 is a cross-sectional view schematically illustrating a processof a method of manufacturing a display apparatus, according to anembodiment. In the manufacturing method according to embodiments of thepresent disclosure, after the display element 300 is formed, a cappinglayer 160, which includes an organic compound, may be formed in thedisplay area DA before the encapsulation layer 500 is formed. Thecapping layer 160 may include the organic compound which increases involume or is gasified or evaporated when the laser beam is irradiatedtherein (e.g., thereto). The capping layer 160 may planarize the displayarea DA.

At this time, the sacrificial layer 420 may be concurrently (e.g.,simultaneously) formed together with the capping layer 160 by using thesame material (e.g., substantially the same material) as the cappinglayer 160. The encapsulation layer 500 may be formed in a single body inboth the display area DA and the pad area PA. When the substrate 100 iscut by the laser beam irradiation, cracks CR may be formed in theportion of the encapsulation layer 500 above the sacrificial layer 420.

In the above-described method of manufacturing a display apparatusaccording to the previous embodiment and the above-described method ofmanufacturing the display apparatus according to the present embodiment,it is possible to perform a process of forming an organic layer, suchas, for example, the intermediate layer 320 or the capping layer 160, inthe display area DA of the substrate 100 and to concurrently (e.g.,simultaneously) perform a process of forming the sacrificial layer 420in the pad area PA of the substrate 100 when the process of forming anorganic layer, such as the intermediate layer 320 or the capping layer160, is performed in the display area DA of the substrate 100, therebysimplifying the manufacturing method. The sacrificial layer 420 may notbe formed when the intermediate layer 320 or the capping layer 160 isformed, but may be formed during a process of forming any organic layerin the display area DA of the substrate 100, by using the same material(e.g., substantially the same material) of the organic layer.

FIGS. 11 and 12 are cross-sectional views schematically illustrating aprocess of a method of manufacturing a display apparatus according to anembodiment. In the manufacturing method according to embodiments of thepresent disclosure, when the encapsulation layer 500 is formed, a firstinorganic encapsulation layer 510 is formed as an integral layer on boththe display area DA and the pad area PA, and then an organicencapsulation layer 520 is formed over the first inorganic encapsulationlayer 510. The encapsulation layer 500 may include a first portion 521and a second portion 522, which is spaced apart from the first portion511 and corresponds to the pad area PA. Here, the statement “when thesecond portion 522 corresponds to the pad area PA” may be considered tomean “when the second portion 522 may correspond to at least a portionof the pad area PA.” The encapsulation layer 500 including the firstportion 511 and the second portion 522 may be formed by using an inkjetprinting method.

Thereafter, a second inorganic encapsulation layer 530 is formed in thedisplay area DA and the pad area PA in a signal body to at leastpartially cover (e.g., completely cover) the first portion 521 and thesecond portion 522. The first inorganic encapsulation layer 510 and/orthe second inorganic encapsulation layer 530 may be formed according toa deposition process and may include silicon nitride, silicon oxideand/or silicon oxynitride or may include metal oxide, metal nitride,metal oxynitride, and/or metal carbide. The organic encapsulation layer520 may include polyacrylate, polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polycarbonate, polyimide, polyethylenesulfonate, polyoxymethylene, polyarylate, and/or epoxy. The organicencapsulation layer 520 may include a monomer and then the monomer maybe converted into polymer, according to embodiments of the manufacturingmethod.

In the above-described encapsulation layer 500, an adhesive forcebetween the first inorganic encapsulation layer 510 and the organicencapsulation layer 520 may be greater than an adhesive force betweenthe sacrificial layer 420 and the first inorganic encapsulation layer510. In this case, when the laser beam is irradiated to cut thesubstrate 100, a volume of at least a portion of the sacrificial layer420 may be increased or the portion of the sacrificial layer 420 may begasified or evaporated. When the portion of the encapsulation layer 500in the pad area PA is removed after the cracks CR formed in the firstinorganic encapsulation layer 510 and/or the second inorganicencapsulation layer 530 grow, the first inorganic encapsulation layer510, the organic encapsulation layer 520, and the second inorganicencapsulation layer 530 may be concurrently (e.g., simultaneously)separated from the sacrificial layer 420 and the lower elements whilethe first inorganic encapsulation layer 510, the organic encapsulationlayer 520, and the second inorganic encapsulation layer 530 areprevented from being separated from each other (or a likelihood oramount of such separation is reduced), as illustrated in FIG. 12.

When the encapsulation layer 520 is formed, the second portion 522 ofthe encapsulation layer 500 may correspond to the sacrificial layer 420described above. In this case, when at least a portion of theencapsulation layer 500 in the pad area PA is removed, at least aportion of the first inorganic encapsulation layer 510 in the pad areaPA, the entire (e.g., substantially the entire) second portion 522 ofthe organic encapsulation layer 520, and at least a portion of thesecond inorganic encapsulation layer 530 in the pad area PA may beremoved together. As a result, a part of the encapsulation layer 500where the second inorganic encapsulation layer 530 contacts the firstinorganic encapsulation layer 510 extends to a portion of the pad areaPA outside the pads 410. Here, the portion of the pad area PA adjoinsthe display area DA. Further, the first end surface 501ES of theencapsulation layer 500 facing the pads 410 is substantiallyperpendicular to an upper surface of the substrate 100.

In this case, as illustrated in FIG. 12, the first end surface 501ES ofthe encapsulation layer 500 (See FIG. 8) includes a lower end surface501LES which is disposed closest to the substrate 100, an upper endsurface 501UES which is disposed farthest from the substrate 100, and anintermediate end surface 501MES between a lower cross-sectional surfaceof the lower end surface 501LES and the upper end surface 501UES. Across-sectional surface of the intermediate surface 501MES may bereferred to as a portion of the second inorganic encapsulation layer 530which contacts the second portion 522 of the encapsulation layer 500. Inthis case, a roughness of the lower end surface 501LES and a roughnessof the upper end surface 501UES may be greater than a roughness of theintermediate end surface 501MES. Since the intermediate end surface501MES is a portion of the second inorganic encapsulation layer 530which contacts the second portion 522 of the encapsulation layer 500,the intermediate end surface 501MES is smooth relatively to the lowerend surface 501LES and the upper end surface 501UES. Since the cracks CRformed in the first inorganic encapsulation layer 510 and the secondinorganic encapsulation layer 530 are grown, and then the firstinorganic encapsulation layer 510 and the second inorganic encapsulationlayer 530 are removed, the roughnesses of the lower end surface 501LESand the upper end surface 501UES may be relatively greater than theintermediate end surface 501MES.

FIG. 13 is a cross-sectional view schematically illustrating a processof a method of manufacturing a display apparatus according to anembodiment. In the method of manufacturing the display apparatusaccording to this embodiment, after the encapsulation layer 500 isformed, an additional organic layer 430 is formed over a portion of theencapsulation layer 500 which is disposed over the sacrificial layer420. As illustrated and described in FIG. 5, the cracks CR are formed inthe encapsulation layer 500. When at least a portion of theencapsulation layer 500 in the pad area PA is removed after the cracksCR are grown, the portion of the encapsulation layer 500 and the entire(e.g., substantially the entire) additional organic layer 430, which arein the pad area PA, may be concurrently (e.g., simultaneously) removed.

When the cracks CR formed in the encapsulation layer 500 grown, and thenat least a portion of the encapsulation layer 500 is removed in the padarea PA, a portion of the encapsulation layer 500, which is to beremoved, may remain in the pad area PA without being removed. In aprocess of forming the cracks CR in the encapsulation layer 500 andgrowing the formed cracks CR, the portion of the encapsulation layer 500may remain in the pad area PA of the substrate 100 without being removedwhen the portion of the encapsulation layer 500 is physically separatedfrom other portions of the encapsulation layer 500 to be removed.

However, in the method of manufacturing the display apparatus accordingto the present disclosure, the additional organic layer 430 may bedisposed over the encapsulation layer 500 and may function as anadhesive to couple (e.g., connect) all (e.g., substantially all) of theportions of the encapsulation layer 500, which are to be removed, toeach other, in the process of growing the cracks CR in the encapsulationlayer 500 and separating the portion of the encapsulation layer 500 fromthe other portions of the encapsulation which are to be removed.Accordingly, all (e.g., substantially all) of the portions of theencapsulation layer 500, which is to be removed, may be concurrently(e.g., simultaneously) removed. In order to do this, an adhesive forcebetween the encapsulation layer 500 and the additional organic layer 430may be greater than an adhesive force between the encapsulation layer500 and the sacrificial layer 420. The additional organic layer 430 mayinclude, for example, polyacrylate, polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polycarbonate, polyimide, polyethylenesulfonate, polyoxymethylene, polyarylate, and/or epoxy. The additionalorganic layer 430 may be formed to correspond to the sacrificial layer420 and may be formed according to the inkjet printing method. Theforming the additional organic layer 430 may be used in the method ofmanufacturing the display apparatus according to the present embodimentand also the method of manufacturing the display apparatus according tothe previously described embodiments and modified examples.

In the above-described embodiments, a process of washing the pad area PAmay be performed after a portion of the encapsulation layer 500 isremoved. In this case, a CO₂ dry washing process may be used to wash thepad area PA.

Although a case in which the display element is the organiclight-emitting element is described above, the present disclosure is notlimited thereto. For example, the portion of the encapsulation layer 500may be removed in the pad area PA according to the above-describedmethod even when other display elements are formed in the display areaDA of the substrate 100.

Meanwhile, the present disclosure is not limited to the method ofmanufacturing the display apparatus. A display apparatus manufacturedaccording to the above-described method may be within the scope of thepresent disclosure. In such a display apparatus, the encapsulation layer500 may at least partially cover (e.g., completely cover) the displayarea DA and thus at least partially cover (e.g., completely cover) thedisplay elements, and in the encapsulation layer 500, a roughness of thefirst end surface 501ES facing the pads 410 is greater than a roughnessof the second end surface 502ES facing away the pads 410 and roughnessesof the third and fourth end surfaces E503ES and 504ES, as illustrated inFIGS. 8 and 9.

In the display apparatus which is also within the scope of the presentdisclosure, when the encapsulation layer 500 includes the firstinorganic encapsulation layer 510, the organic encapsulation layer 520,and the second inorganic encapsulation layer 530, the first end surface501ES of the encapsulation layer 500 may include the lower end surface501LES which is disposed closest to the substrate 100, the upper endsurface 501UES which is disposed farthest from the substrate 100, andthe intermediate end surface 501MES between the lower end surface 501LESand the upper end surface 501UES. The roughnesses of the lower endsurface 501LES and the upper end surface 501UES may be greater than aroughness of the intermediate end surface 501MES.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

It will be understood that, although the terms “first,” “second,”“third,” etc., may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, a first element, component, region, layer or sectiondescribed below could be termed a second element, component, region,layer or section, without departing from the spirit and scope of thepresent disclosure. For example, as described herein “a first inorganicencapsulation layer” may be “a second inorganic encapsulation layer.”

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,”“above,” “upper,” and the like, may be used herein for ease ofexplanation to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or in operation, in additionto the orientation depicted in the figures. For example, if the devicein the figures is turned over, elements described as “below” or“beneath” or “under” other elements or features would then be oriented“above” the other elements or features. Thus, the example terms “below”and “under” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (e.g., rotated 90 degrees or at otherorientations) and the spatially relative descriptors used herein shouldbe interpreted accordingly.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to,” or “coupled to” another element or layer, itcan be directly on, connected to, or coupled to the other element orlayer, or one or more intervening elements or layers may be present. Inaddition, it will also be understood that when an element or layer isreferred to as being “between” two elements or layers, it can be theonly element or layer between the two elements or layers, or one or moreintervening elements or layers may also be present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a” and “an” are intendedto include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes,” and “including,” when used inthis specification, specify the presence of the stated features,integers, acts, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, acts, operations, elements, components, and/or groups thereof.

As used herein, the terms “substantially,” “about,” and similar termsare used as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art. Further, the use of “may” when describing embodiments of thepresent disclosure refers to “one or more embodiments of the presentdisclosure.” As used herein, the terms “use,” “using,” and “used” may beconsidered synonymous with the terms “utilize,” “utilizing,” and“utilized,” respectively.

Also, any numerical range recited herein is intended to include allsubranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein, and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims,and equivalents thereof.

What is claimed is:
 1. A method of manufacturing a display apparatus,the method comprising: preparing a substrate comprising a display areaand a pad area outside of the display area; forming a sacrificial layerin the pad area; forming an encapsulation layer over the display areaand the pad area; forming cracks in at least a portion of theencapsulation layer by increasing a volume of the sacrificial layer orby gasifying or evaporating at least a portion of the sacrificial layer;and removing at least a portion of the encapsulation layer in the padarea.
 2. The method of claim 1, wherein the forming of the sacrificiallayer comprises concurrently forming an organic layer in the displayarea and the sacrificial layer.
 3. The method of claim 1, wherein theforming of the sacrificial layer comprises concurrently forming anintermediate layer interposed between a pixel electrode and an oppositeelectrode in the display area, and the sacrificial layer.
 4. The methodof claim 1, further comprising: forming a display element in the displayarea, wherein the forming of the sacrificial layer comprisesconcurrently forming a capping layer comprising an organic compound andat least partially covering the display element in the display area, andthe sacrificial layer.
 5. The method of claim 1, wherein the forming ofthe cracks comprises irradiating a laser beam to the portion of theencapsulation layer that is above the sacrificial layer.
 6. The methodof claim 5, wherein the forming of the cracks comprises using the laserbeam having an absorbance in an organic compound greater than aninorganic compound.
 7. The method of claim 1, wherein the forming of theencapsulation layer comprises forming an inorganic layer.
 8. The methodof claim 1, further comprising: increasing an area of the encapsulationlayer, in which the cracks are formed, by applying a force to theencapsulation layer that is above the sacrificial layer.
 9. The methodof claim 8, wherein the increasing of the area comprises using a roller.10. The method of claim 1, wherein the forming of the encapsulationlayer comprises: forming a first inorganic encapsulation layer over thedisplay area and the pad area; forming an organic encapsulation layerover the first inorganic encapsulation layer, the organic encapsulationlayer comprising a first portion corresponding to the display area and asecond portion separate from the first portion and corresponding to thepad area; and forming a second inorganic encapsulation layer in thedisplay area and the pad area to at least partially cover the firstportion and the second portion of the organic encapsulation layer. 11.The method of claim 10, wherein an adhesive force between the firstinorganic encapsulation layer and the organic encapsulation layer isgreater than an adhesive force between the first inorganic encapsulationlayer and the sacrificial layer.
 12. The method of claim 10, wherein theremoving of the portion of the encapsulation layer comprises removing atleast a portion of the first inorganic encapsulation layer in the padarea, the entire second portion of the organic encapsulation layer, andat least a portion of the second inorganic encapsulation layer in thepad area.
 13. The method of claim 1, further comprising: forming anadditional organic layer over the portion of the encapsulation layerthat is over the sacrificial layer, wherein the removing of the portionof the encapsulation layer comprises removing the portion of theencapsulation layer that is over the sacrificial layer, and the entireadditional organic layer.
 14. The method of claim 13, wherein anadhesive force between the encapsulation layer and the additionalorganic layer is greater than an adhesive force between theencapsulation layer and the sacrificial layer.